Effects of epidermal growth factor and mitogenic pathway inhibitors on rat colon cancer proliferation in vitro

The proliferative responses of two rat colon cancer cell lines (Per192NR and Per237) to concentrations of epidermal growth factor (EGF) were assessed alone, or in combination with calcium sequestration or inhibitors of protein kinase A, C (PKA and PKC). Up to 160nM of EGF stimulated cell proliferation in Per237 cells, but was ineffective in Per192NR cells. In both cell lines all inhibitors failed to alter basal proliferation. In Per192NR cells the combination of 5 to 20nM EGF and inhibitor resulted in a biphasic reduction in basal proliferation which was lost by 20nM. In the Per237 cells only 10nM EGF and PKA inhibitor reduced proliferation. Tumours derived from the same origin respond differently to EGF-induced mitogenesis.